Friday, March 2, 2012


Alright, well other than sounding like the worst STD ever conceivable, this story is actually pretty cool. I mean, how else can you combine both Zombies and Marine Biology?!?! I found this story through the awesomeness of Stumbleupon which brought me to this University of Hong Kong website.
There is no small number of unsettling parasites crawling, flying, and swimming about the Earth, the lucky ones hitching rides on hapless host organisms. And while many parasites are harmless, or even beneficial in their way, others can wreak havoc with their hosts’ existence. The worst of these offenders can actually force their host to do their will.

A tiny barnacle called Sacculina is one such parasite. Upon finding a host crab, a female Sacculina will crawl over the crab’s surface until she finds a chink in the armor: a joint. She then ejects her protective shell, reducing herself to a gelatinous blob, and invades.

Inside the host, the parasite grows long, root-like tendrils throughout the crab’s body, eventually emerging as a bump on the its underside. During this process she renders the crab infertile, and creates a small opening in the crab’s back that will allow a male Sacculina to make residence there. Soon the crab is filled with millions of Sacculina eggs and larvae, and like a zombie, the crab cares for these eggs and larvae as though they were its own, losing all interest in mating. When a male crab is infected, the parasite alters its physiology and behavior to be female, to better care for the Sacculina’s young.

The parasite basically rewires the crab for its own ends, and the crab becomes a helpless vehicle, expending its energy caring for the young organisms that will move on to inflict themselves upon other crabs.


  1. Got to love stumbleupon! This is really neat. You said that the barnacle was a parasite to the carb, my question is how can you tell the difference between this barnacle and other ones common to intertidal areas and other places in the ocean. Another question I have is, can the barnacle affect humans if they come in close contact with or somehow touch or attach to a human? This is crazy how through time a barnacle can evolve to perform these parasitic tasks. Very, very interesting and intriguing.

    1. Im not sure if you can tell the difference between these barnacles and others. The barnacle leaves its shell to get inside the crab, so I guess and empty shell on the crab could indicate its presence. It says the males come in later, so they have to be hanging out somewhere before that point, I am just not sure if you can tell the difference. As for attacking humans I assume not, just because the differences between a human and a crab. But your question made me think of the Brain Slug from Futurama. Over time I assume they could adapt to attacking humans, that would be a good evil plot to take over the world!

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